controlling a stepper with a simple trigger switch

[routercnc]

If you really want to move the CNC machine independant of a PC then you can in theory connect a function generator to one of the step/pulse inputs to a BOB. It would move the motor at the speed set by the function generator. Select square wave, ~5v output, frequency set to give the required speed. For direction you need to supply 0v or 5v to the direction pin.

If you do this you probably need to isolate the PC parallel port temporarily to avoid putting 5v into an output.

I believe this is essentially what the MPG does but it goes through the software to retain position.

If you go direct you are bypassing Mach/Linux so I think it would completely loose position.

Perhaps a macro would be a better option assigned to a spare button on an MPG.

[phill05]

Thanks Routercnc,
It's not what I am looking for, forget the machine, no cnc, no computer, loose stepper motor is sat on a bench is it possible to power it to turn CCW & CW with a trigger switch off a pistol drill or 2 buttons and what other components would I need to make it work.

Phill

[phill05]

I'll try to explain a little better, this is not a cnc machine, but it has an X axis left to right, the guy holds 2 handles 1 in each hand when he has moved to the right he has to manually move the head down IE: put on a cut but when he take 1 hand off the handle does not matter which handle the spindle stops rotating. the machine only rotates when the guy has both hands on.
What I want to do is put a stepper motor and control it with either a trigger switch or two buttons for the guy to power the head up & down without him taking either hand off the handles and the spindle keeps revolving.

Phill